Patients undergoing liver surgery due to benign or malignant liver tumors are evaluated in a multidisciplinary way: surgeons, gastroenterologists, anesthesiologists, intensive care physicians, radiologists, oncologists and pathologists are involved in the perioperative evaluation. Surgical know-how, combined with a broad spectrum of diagnostic and therapeutic options stand for a high degree of safety and effectiveness of perioperative treatment. The general physical status of the patient, the type and extend of liver disease, as well as the complexity of liver resection have significant impact on perioperative morbidity and mortality. Appropriate preoperative evaluation and preparation of the patient is therefore of utmost importance. This allows for adequate risk assessment and further helps to define risk management strategies.